Informations et ressources scientifiques
sur le développement des zones arides et semi-arides

Accueil du site → Master → Etats Unis → 2020 → PLANT LITTER DECOMPOSITION DIFFERS WITH SPECIES AND SOIL RESOURCES IN A CHIHUAHUAN DESERT GRASSLAND

University of New Mexico (2020)

PLANT LITTER DECOMPOSITION DIFFERS WITH SPECIES AND SOIL RESOURCES IN A CHIHUAHUAN DESERT GRASSLAND

Lopez Andrea

Titre : PLANT LITTER DECOMPOSITION DIFFERS WITH SPECIES AND SOIL RESOURCES IN A CHIHUAHUAN DESERT GRASSLAND

Auteur : Lopez Andrea

Université de soutenance : University of New Mexico

Grade : Master of Science in Biology 2020

Résumé
Uncertainties surround the extent to which diversity can mitigate the effects of climate change and anthropogenic activity on ecosystem functions. In desert grasslands, changes to water availability and soil nitrogen, two primary resources that limit ecosystem processes, can have lasting impacts on nutrient cycling. We used grass litter from Bouteloua eriopoda, Bouteloua gracilis, Pleuraphis jamesii, and Sporobolus spp. to assess the effects of soil resources on single- and multi-species decomposition in a Chihuahuan Desert grassland in central New Mexico, USA. Litterbags were deployed in a factorial experiment that manipulated rain pulse size (5- vs. 20-mm) and frequency (weekly vs. monthly), and soil nitrogen content during the monsoon season. Decay did not significantly differ among pulse-sized thresholds. We found significant differences among species so that the more palatable grasses, B. gracilis and P. jamesii, decayed faster (k = 0.48 y-1 and 0.33 y-1, respectively) than B. eriopoda (k = 0.24 y-1). Although not significant, the decay of litter mixtures was enhanced in the 5-mm·week-1 (k = 0.53 y-1) and 20-mm·month-1 (k = 0.499 y-1) treatment relative to the water control (k = 0.31 y-1) when nitrogen was not limiting. Nitrogen immobilization persisted only in B. eriopoda and litter mixtures after one year. Future changes in rainfall regimes will have limited impacts on nutrient cycling in desert grasslands at current rates of atmospheric nitrogen deposition. However, high rates of nitrogen deposition will likely intensify the effect of pulse-sized thresholds on nutrient cycling. We conclude that species composition is critical for ecosystem functioning. Mots clés : Sevilleta, Deep Well, mixed grassland, pulse-sized thresholds, litter mixtures, species traits Présentation

Version intégrale (7,0 Mb)

Page publiée le 28 décembre 2021